An employee showing up for work early Tuesday discovered thick, black smoke inside Epic Landscape Production’s Design Center in Olathe.

The employee found the fire about 6 a.m. when she opened one of the doors to the office and warehouse building at 15460 S. Keeler St. in southern Olathe, according to Capt. Mike Hall, a spokesman for the Olathe Fire Department.

The smoke filled the office area and attached warehouse from ceiling to floor. Firefighters put out the fire in about five minutes, containing it to one room in the office, Hall said.

Investigators are working to determine how the fire started, he said.

The employee suffered from minor smoke inhalation but refused treatment.